1. Field of the Invention
The present disclosure relates to a magnetic resonance imaging (MRI) apparatus for diagnosing various diseases using MRI, and a manufacturing method thereof.
2. Description of the Related Art
In general, a medical imaging system is an apparatus for providing imaging information about an internal area of a patient. The medical imaging system includes an X-ray machine, an ultrasonic diagnostic instrument, a computer tomography (CT) scanner, a magnetic resonance imaging (MRI) apparatus, etc.
The MRI apparatus holds an important position in the field of medical imaging diagnosis because image-taking conditions are relatively free and the MRI apparatus can provide excellent delectability and various diagnosis information images with respect to soft tissue.
The MRI causes nuclear magnetic resonance (NMR) in the hydrogen atomic nuclei of the human body through the use of a magnetic field that is harmless to humans and RF, which is non-ionizing radiation, to thus image the densities and physical or chemical characteristics of the atomic nuclei.
In more detail, the MRI apparatus supplies a specific frequency and energy to atomic nuclei in the state in which a constant magnetic field has been applied to the atomic nuclei, in order to cause the atomic nuclei to release energy, and the MRI apparatus converts the energy released from the atomic nuclei to signals, thereby being able to visually diagnose the inside of the human body.
When a magnetic field is applied, protons configuring atomic nuclei are arranged in the direction of the magnetic field because the protons have spin angular momentum and magnetic dipole moment, and the atomic nuclei perform precession with respect to the direction of the magnetic field. The precession causes nuclear magnetic resonance so that an image of the inside human body can be acquired through the nuclear magnetic resonance.
Meanwhile, the MRI apparatus applies a gradient field to a static field formed in a subject to thus acquire an image of the subject. In order to form a gradient field in a static field, it is necessary to supply a pulse-type current to a gradient coil unit.
If a pulse-type current is applied to the gradient coil unit, eddy current flows through a static coil unit for forming a static field in the subject, due to electromagnetic induction. The eddy current induced in the static coil unit also induces a magnetic field that obstructs acquisition of normal images, resulting in degradation of image quality.
Accordingly, in order to avoid degradation of image quality due to such eddy current flowing through a static coil unit for forming a static field in the subject, there is a need in the art for a technology capable of suppressing the influence of the eddy current.